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A276939
Row 2 of A276945: a(n) = A002110(n) + A002110(n+1).
3
3, 8, 36, 240, 2520, 32340, 540540, 10210200, 232792560, 6692786100, 207030183360, 7621298624940, 311671001662020, 13387011595197240, 627972543920161440, 33204048259778536140, 1955349508631402683800, 119211141709561183622340, 7975609932439674026862360, 565799151677779228023294480, 41287621429375723111588738860
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OFFSET
0,1
COMMENTS
a(n) = number whose primorial base representation (A049345) begins with digits "11", followed by n zeros: 11, 110, 1100, 11000, 110000, ...
LINKS
Michael De Vlieger, Table of n, a(n) for n = 0..349
Index entries for sequences related to primorial base
FORMULA
a(n) = A002110(n) + A002110(n+1).
MATHEMATICA
Total /@ Partition[FoldList[Times, 1, Prime@ Range[20]], 2, 1] (* Michael De Vlieger, Jun 24 2023 *)
PROG
(Scheme) (define (A276939 n) (+ (A002110 n) (A002110 (+ 1 n))))
(PARI) a(n) = factorback(primes(n)) + factorback(primes(n+1)); \\ Michel Marcus, Nov 23 2022
CROSSREFS
Row 2 of A276945 (column 2 of A276943).
Cf. A002110, A049345.
Sequence in context: A020111 A367640 A111543 * A188327 A024039 A147523
Adjacent sequences: A276936 A276937 A276938 * A276940 A276941 A276942
KEYWORD
nonn,base
AUTHOR
Antti Karttunen, Sep 24 2016
STATUS
approved

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Last modified November 27 04:21 EST 2024. Contains 378136 sequences.
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